Genetic information and relationships - DNA & Protein synthesis Flashcards
Define the term gene
A base sequence of DNA that codes for the amino acid sequence of polypeptide and functional RNA
What is the gene locus?
The specific position of a gene on a chromosome
What is an intron
Non-coding sections of DNA and are found within genes
What is an exon
Coding sections of DNA
What are non-coding multiple repeats
Non-coding repeats of base sequences found between genes
Why can much of eukaryotic DNA be considered as non-coding
what are the proteins called that associate with eukaryotic DNA
Histone proteins
Define the term chromosome
A condensed DNA molecule associated with histone proteins
Describe the DNA in eukaryotes
- DNA molecules are longer
- DNA molecules are linear molecules
- DNA molecules are associted with proteins called histones
Describe the DNA in prokaryotes
- DNA molecules are shorter
- DNA molecules are circular
- DNA molecules are not associated with histone proteins
Describe the DNA in chloroplasts and chloroplasts
Circular DNA
Why is the genetic code described as degenerate
Most amino acids are coded for by more than one triplet
Why is the genetic code described as non-overlapping
Each base is only read once
Why is the genetic code described as universal
Each triplet codes for the same amino acid in all organisms
What is the genome
The complete set of genes in a cell
What is the proteome
The full range (variety) of proteins that a cell is able to produce
Differences between DNA nucleotide and an RNA nucleotide
- DNA (Deoxyribose sugar)
- RNA (Ribose sugar)
- DNA (Thymine)
- RNA (Uracil)
- DNA (Longer molecule)
- RNA (Shorter molecule)
- DNA (Double stranded)
- RNA (Single stranded)
- DNA (Base pairing)
- RNA (No base pairing)
Structure of mRNA
- Straight chain
- Single chian
- Base sequence is complementary to DNA code
Function of mRNA
Carries ‘code’ from nucleus to cytoplasm
Structure of tRNA
- Clover leaf shape
Function of tRNA
- Carries amino acids to the ribosomes
- Amino acid binding site
What is a triplet code
A sequence of 3 DNA bases that code for a specific amino acid
What is a codon
A sequence of 3 bases coding for an amino acid
What is an anticodon
A sequence of 3 bases tht are complementary to the codon on mRNA
What is pre-mRNA
MRNA that contains introns and exons
What is splicing
Where the introns from the pre-mRNA are removed to eave a molecule of mRNA
Describe how mRNA is formed by transcription in eukaryotes
- Hydrogen bonds between DNA bases break
- Only one DNA strand acts as a template
- Free RNA nucleotides align by complementary base pairing
- RNA polymerase joins adjacent RNA nucleotides, forming posphodiester bonds
- A bonds to Uracil instead of thymine
- Pre-mRNA is splice to form mRNA
Describe how a polypeptide is formed by the translation of mRNA
- mRNA attaches to ribosomes
- tRNA anticodons bind to complementary mRNA codons
- tRNA brings a specific amino acid
- Amino acids join by peptide bonds with the use of ATP
- tRNA is released after the amino acid is joined to the polypeptide
- The ribosome moves along the mRNA to form the polypeptide
